Import GLSL-Shader into blender
Blender doesn't have way to directly interpret GLSL shaders. You can, however, use a BGE python script that tells blender to use a particular shader during a game's runtime.

To do this you will need two things: your GLSL shader formatted in the following way (inside of a text datablock)...

import bge

cont = bge.logic.getCurrentController()

VertexShader = """
   void main(){
      //your vertex shader here
   }
"""

FragmentShader = """
   void main(){
      //your fragment shader here
   }
"""

mesh = cont.owner.meshes[0]
for mat in mesh.materials:
    shader = mat.getShader()
    if shader != None:
        if not shader.isValid():
            shader.setSource(VertexShader, FragmentShader, 1)


and a bit of a logic brick setup: